Automatic telephone system



Dec. 25, 1928. 1,696,254

w. PINELL AUTOMATIC TELEPHONE SYSTEI Filed June 13; 1927 Inventor" Mani Pinsu lit a wil Patented 25, 1928.

UNITED. STATES 1,696,254 PATENT OFFICE.

WALTER PINELL, BERLIN, GERMANY, ASSIGNOR 'IO SIEMENS & HALSKE AKTIEN- GESELLSCHAFT,,WEBNERWERK, OF SIEMENSSTADT, NEAR BERLIN, GERMANY.

AUTOMATIC TELEIHONE SYSTEM.

Application filed June 18, 1927, Serial No.

The present invention relates to a circuit arrangement for testing relays 1n telephone circuits, particularly those employing selectors. Known already are arrangements in which in order to obtain a short period of response, testing relays are premagnetized by special auxiliary means. According to the present invention these latter are now avoided in that, before the commencement of a test (for instance, when the selector is engaged), the energizing windin of the testing relay is placed n circuit by switching means, so that the said relay may be preinagnetized.

The present invention is shown 1n the attached drawing, but the invention is not limited to this example, and can be applied to all kinds of stepping switch mechanisms, such as prcselector devices, second group selectors and line selectors, If, in the present example, a first group selector GVV is engaged by a pre-selector, then the relays A, B, and C respond. The relay A actuates its alternating contact a and the relay 0 its contacts 0 and 0 The relay C closes a holding circuit for itself over: Earth, winding of relay V alternating contact a, winding II of the relay C, contact 00 battery, earth.

In this circuit, the relay V is also energiaed and the contacts 112 2e2 341 and 4M are thrown over. Over the contact 1 21 the following circuit is now closed: Earth, battery, resistance W, contact 1e2 winding II of the relay P, earth.

The winding II of the relay P receives the current, and, according to the invention, through this winding, the testing relay P is preinagnetized before the commencement of the test over the contmt lc On account of the resistance W the winding II of the testing relay P does not receive enough current to cause relay P to operate its contacts 30. By sending out the first series ofimpulses on the part of the calling subscriber, the group selector GVV is set to the number tens level. The relays A and B, during the sending out ofthe impulse series, are energized and deenergized in accordance with the current impulses and reeat the impulses to the steppingrelay J.

he battery feed supply to the calling subscribers station is also made over the relays A. and B. The current impulses are transmitted to the relay J over the following 198,345, and in Germany October 12, 1926.

route: Battery, earth, Winding of the relay J, back contact 122 contact 40 earth.

The lifting magmet H of the group selector GriVV receives the current impulses sent out over the contact 2". During the sending out of current impulses the relays C, V and V remain energized.

After the termination of the impulse se ries the relay V deenergizes; thus, it is in working position from the beginning up to the end of the impulse series. During the first lifting ste the vertical ofi normal con tact k is opened and vertical ofl-normal contacts and k are closed. The winding I of the relay C is deprived of current due to the opening of the contact 12 but the relay holds itself over its winding II. The group selector G'W is maintained busy by earth being applied over contact 0 resistance W releasing contact m to the testing wire of the group selector GW. After the sending of the first impulse series and the closing of the off-normal contact 76 the following circuit is established for the rotary magnet D: Contact 10 back contact 39 back contact 110 contact Ee back contact 2' winding of the rotary magnet D, battery, earth. By hunting the group selector GW now seeks a junction line leading to the next impulse register. Upon the rotary magnet D functioning, the alternating contact 61 is thrown over, so that the relay J is made ,to respond over this circuit: Earth, alternating contact d, winding of the relay J, battery, earth.

The circuit for the lifting magnet H is interrupted by the opening of the rotary oil" normal shaft contact RON. l/Vhen the relay J responds the circuit for the rotary magnet d is broken through the back contact 2' and when the rotary magnet 62 deenergizes, the circuit for the relay J is opened by the alternating contact d and the relay J deenergizes. This alternating action between the relay J and the rotary magnet D continues until a free junction line is found and the circuit for the rotary magnet d is broken over ,the back contact p When an idle junction line and switch is found, then the relay P responds over the following circuit: Earth, battery, (on the incoming test lead of the idle switch), switchin arm a of the group selector, winding I o the relay P, alternating contact in, winding II of the relay P, earth.

The testing relay P responds very rapidly, because, according to the invention, the testing relay P is provided with a pre-magnetized windin viz, the winding II. As already described, the winding 1 of the relay 1 receives current due to the functioning of the relay V. The energizing winding of the relay P (winding II) is, at the same time, the premagnetizing winding for the testing relay P. After the functioning of the latter, a holding circuit is closed for the same, viz, over: Earth, contact p", windlng I of the testing relay P, (holding winding of the testing relay), contact arm 0, testwire, battery, earth, (in the seized switch).

The speakin wires a and b are switched through over t e contacts and 17 After the conclusion of a call ti ie group selector GVV is released in the following manner. Relay A deenergizes when the calling subscriber hangs up and said relay at contact a short circuits relay C whereupon. the latter relay after an interval deenergizes. Relay C, upon deenergizing, opens the circuit of relaysV and V which deenergize and complete a circuit for operating the release magnet M. At contact 0 and m the holding circuit to the preceding switch is opened. The releasing magnet o the group selector receives current over the following path: Earth, battery, winding of the releasing magnet M, back contact 31:, back contactjo", back contact p, off-normal contact is, earth.

\Vhat is clalmed is:

1. In an automatic switch, a test relay, 0. switching device, and means controlled by said switching device for pro-magnetizing but not operating said test relay responsive to the seizure of said switch in order to assist said relay to operate when an idle line is encountered by said switch.

2. In a telephone system, an automatic switch, trunk lines accessible to said switch, a test relay in said switch adapted to be energized to seize one of said trunk lines, a switching device in said switch, means controlled by said device for pre-magnetizing said test relay responsive to the seizure of said switch, means for operating said switch to test said trunk lines, and means for operating said relay res onsive to said switch encountering an i le one of said trunk lines, said pre-magnetization effective to assist in the operation of said relay.

3. In an automatic switch having access to trunk lines, a test relay having two windings, means responsive to,the seizure of said switch for premagnetizing said relay over one of its windings, means for operating said switch to test for an idle one of said trunk lines, and a circuit for energizing said relay including the test lead of an idle trunk and the two windings of said relay in series.

4, In an automatic switch having access to trunk lines, a test relay having two windings, one of said windings being normally short circuited, means responsive to the seizure of said switch for opening the short circuit around said first winding and for closing a circuit to pre-magnetize said second winding, means for operating said switch to test for an idle one of said trunk lines, and a circuit for energizing said relay including the test lead of an idle trunk and the two windings of said relay in series.

5. In an automatic switch, a test relay, line wipers, a air of talking conductors, contacts on said relay normally disconnecting said conductors from said wi )ers, a switching device, means controlled y said device for prc-magnetizing said relay responsive to the seizure of said switch, and means for energizing said relay to operate said contacts to connect said conductors with said wipers.

6. In a telephone system, an automatic switch, trunk lines accessible to said switch, a test relayin said switch, a switching device in said switch, means controlled by said device for re-magnetizing said relay res onsive to t e seizure of said switch, means f r operating said switch to test said trunk lines, means for energizing said relay responsive to said switch encountering an idle one of said trunk lines, and contacts on said relay for connecting a busy potential to the test contact of the seized trunk line.

In witness whereof, I hereunto subscribe my name this 11th da of May, A. D. 1927.

W ALTER PINELL. 

